PTL 1 discloses a drive circuit configured to drive a power transistor, in particular, a drive circuit involved with noise reduction. This drive circuit detects a current which flows into a gate terminal of a power transistor at the time of application of a voltage to a gate of the power transistor through a gate resistor to turn on the power transistor, and increases a resistance value of the gate resistor when the detection value changes from increase to decrease. A switching speed of the power transistor is thus lowered to suppress generation of conductive and/or radiative noise.